Closure sorting method and apparatus

ABSTRACT

Container closures are sorted before lining by being passed along a sorting track which engages the closure skirt and drives the closure for rotation about the axis of symmetry of the closure, undersized closures being received by a rejection slot in the sorting track, since the slot is dimensioned to block correctly sized closures. Optionally the closures may subsequently be rotated in the reverse direction.

United States Patent Shotbolt et al.

[ Aug. 12, 1975 i 1 CLOSURE SORTING METHOD AND APPARATUS [75] Inventors: Keith Shotbolt, Gerrards Cross;

Alan Eastwood, Langley; John Henry Gait, Ruislip, all of England [73] Assignee: W. R. Gwace & Co., Cambridge,

Mass.

{22] Filed: Feb. 5. 1974 [2i] Appl. No: 439,808

[52] US. Cl. 209/73; 209/99; 198/252 [5 l] Int. Cl. B07C 9/00 [58] Field of Search l. 209/82, 99, I07, 104, 85, 209/73; 198/238. 252, 266

[56] References Cited UNITED STATES PATENTS l,366.l 3() H192! Mueller 209/99 3,30l,397 1/1967 Stutz 209/99 15,66,882 lO/l97l Stampe .7 209/73 $104,780 l2/l972 Aidlin et al. it 209/99 Primary ExaminerAllen N. Knowles Attorney, Agent, or Firm-Armand McMillan; C. E. Parker [57] ABSTRACT Container closures are sorted before lining by being passed along a sorting track which engages the closure skirt and drives the closure for rotation about the axis of symmetry of the closure, undersized closures being received by a rejection slot in the sorting track, since the slot is dimensioned to block correctly sized closures. Optionally the closures may subsequently be rotated in the reverse direction.

11 Claims, 3 Drawing Figures CLOSURE SORTING METHOD AND APPARATUS The present invention relates to closure sorting. and in particular to a method of and apparatus for sorting damaged or malformed closures from otherwise perfectly dimensioned closures.

One commonly used form of closure sorting device consists of a horizontal track defined by spaced wires which support the closure on its peripheral beading.

A further type of conventional sorter is one in which the closures are transported in the horizontal plane around an arcuate path with support under their peripheral skirts on one side of the path by virtue of the pockets of a star wheel advancing the closures. and on the other side of the path by virtue of a concave guide plate spaced outwardly from the star wheel by a distance dependent upon the size of closure to be sorted. At some stage the closures pass over a slot through which they are allowed to fall if they are undersized. This particular form of closure sorter will reject closures which are totally undersized. in other words closures whose maximum diameter is less than the desired threshold value. However. it is by no means certain that a closure which is oval with any major axis equivalent to the correct diameter will be rejected since it is quite possible for the major axis to span the gap between the star wheel pocket and the concave guide even though the minor axis of the oval is undersized. This closure will thus he supported during its passage over the ejector slot.

According to a first aspect of the present invention we provide a method of sorting skirted closures which comprises passing the skirted closures along a sorting track having a rejecting slot dimensioned to receive andersized closures but to block correctly sized closures. rotating each closure about its axis of symmetry as hereinafter defined. as it passes along the supporting track. collecting the closures which successfully pass along the sorting track. and discarding any closures which pass through the rejecting slot. By the term axis of symmetry" we mean that axis ofsymmetry which extends perpendicular to the end wall of the closure.

According to a second aspect of the present invention. we provide a closure sorting apparatus which comprises a sorting track for transporting skirted closures. the said track including laterally spaced closure skirt-supporting surfaces with a closure-rejecting slot therehetween. and at least one serrated surface for engaging the skirts of closures passing along the sorting track to drive the closures in at least one direction of rotation Preferably the closures are driven for rotation in a first direction followed by subsequent driving for rotation in a second direction. More preferably the closure rotating surface consists of serrations formed on the guide track.

Advantagcously the guide track may be formed by spaced side plates. one of which has serrations along a first part of the closure track and the other ol'which has serrations along a second part of the closure track so that the closure is urged for rotation in a first direction along the first closure track part and for rotation in a second direction along the second closure track part. The side plates of the sorting track may. if desired. be replaced by supporting wires or other suitable support members Conveniently means may be provided for varying the width of the closure guide track to adjust the threshold of undersize value at which closures will be rejected.

Desirably the closures may be positively advanced along the sorting track by means of fingers of a feed wheel holding said closure firmly in engagement with the guide and closure-rotating surfaces. More desirably the fingers may be spring-loaded so as to be permitted resiliently resisted motion in a radially inward direction.

Suitably the guide track may he of arcuate form centered on the axis of rotation of the feed wheel and subtending approximately 90 at the horizontal axis of the feed wheel. By this arrangement the undersized closures will be rejected by a combination of the weight force acting on each closure, the centrifugal force effect on each closure and. where applicable. the spring loading urging each closure radially outwardly. Clearly. where spring biasing of the fingers of the feed wheel is employed the biasing spring must not be so strong that the force exerted on the inside of the closure by the indexing finger is sufficient either to impose excessive frictional resistance against rotation of the closure or to damage the interior surface of the closure which may subsequently require lacquering or lining.

The closure sorter in accordance with the present invention is clearly preferable to the known forms of closure sorter in that the closure is now positively driven for rotation so that if it is only locally undersize while being elsewhere correctly dimensioned. the rotation of the closure will ensure that sooner or later the undersized portion spans the rejecting slot and allows the closure to be rejected.

This action has nowhere been employed in prior art closure sorters.

In order that the present invention may more readily be understood. the following description is given. merely by way of example. reference being made to the accompanying drawing. in which:

FIG. I is a side elevational. partly schematic view of the closure sorter in accordance with the present invention".

FIG. 2 is a sectional view taken on the line lI-ll of FIG. 1: and

FIG. 3 is a view similar to FIG. 2 but showing an alternative embodiment.

In FIG. I there is shown the feed wheel I with individual crown-engaging fingers 2 which are resiliently depressible in the radial direction by contact with a closure such as the closure 3 descending into contact with the wheel.

At various stages around the periphery of the feed wheel 1. are several different closures 3a. 311. 3c. 3d. 30 and 3f which are all moving in the anticlockwise sense around the axis of the spindle 4 of feed wheel I.

The closures 3 are fed to the feed wheel along vertically extending chute 5 from a feed hopper (not shown] which gives a constant delivery into the mouth of the chute 5. The sides of the actual sorting track 6 comprise side plates 74:. 7h shown in greater detail in the cross-sectional view of FIG. 2.

From the sorting track 6 the undamaged closures are fed horizontally under a cover plate 8 which strips them from the feed wheel fingers so that they can be fed to some other part of the closure processing line.

Although the closure sorter in accordance with the present invention can be used in any situation where it is desirable to reject damaged or malformed closures or even swarf and trash which may still be present in the closure supply it is particularly convenient for the sorter to be incorporated in a closure lining plant such as that disclosed in our copending Patent application Ser. No. 439.8 l2 filed on Feb. 5. 1974. In this way. the closures can be fed straight from a supply hopper down along the closure sorting track 6 and onto a conveyor carrying the closures around the lining apparatus past the various operating stations.

The shaft 4 of the feed wheel is driven for rotation in the anticlockwise sense directly from the lining apparatus drive so that the peripheral rate of advance of the fingers 2 is commensurate with the desired rate of supply of closures to the closure lining apparatus.

The cross-sectional view of FIG. 2 shows that at the plane represented by the line II-II in FIG. I, the left hand side plate 7(/ has a plurality of serrations or teeth 9 formed along its upper edge while the corresponding upper edge of the opposite. in this case the right-hand. side plate 7h is rounded without any serrations. The serrations 9 are illustrated in FIG. I. and have a peripheral spacing along the line of closure advance equivalent to the pitch of the undulations around the periphery of crown closures to be sorted.

FIG. I also illustrates schematically the presence of further serrations or teeth It) on the right-hand side of the plate 711 at a station nearer the end of the sorting track 6. The three radial planes represented by lines A. B. and C in FIG. I divide the sorting track into two operating lengths. In the first operating length between radial plane A and radial plane B the serrations 9 are formed in the side plate 70 and not on side plate 7/) whereas in the operating length between radial plane 8 and radial plane C the serrations 10 are formed in the side plate 7h but not on side plate 711.

By virtue of the similarity of the pitch between the serrations 9, I0 and the undulations around the periphery of the crown closure it is clear that since the closure-engaging fingers 2 are spring-loaded to hold the closures radially outwardly against the upper shoulders of the side plates 7a and 7b, the undulations of the closure will engage the serrations 9 or H) with a bevel gear action which because of the asymmetry of the serrations will cause the closure to rotate. Thus. when viewing the closure along a direction I] extending radially outwardly of the indexing wheel I. the closure 34! slides without rotation as it is picked up by the closureengaging indexing finger Zu. Upon entering the operat ing length A-B of the sorting rack the closure 3b is now lightly held down by finger 2b and as soon as the peripheral undulations of the closure are picked up by the serrations 9 the closure will commence rotation in the anticlockwise sense as viewed along the direction of arrow II.

Shortly before arriving at radial plane B the closure will ride off the last one of the serrations 9 so as to stop its anticlockwise rotation and will then engage the first of the serrations It) on the opposite side plate 7/) and will then commence rotation in the clockwise sense.

The spacing between the side plates 70 and 7b is such that a correctly formed and undamaged closure 3 can safely ride along the length of the side rails without being pushed down into the space l2 between the two plates 71:. 7h. However. whenever the closure in question is undersize, or even damaged or malformed so that the diametral dimension at any position across the closure is significantly less than the intended diameter of the circular closure. the closure will be allowed to fall into the space I2 and will be ejected by the composite force derived from (u) the action of the spring loaded finger 2. th) the effect of gravity causing the closures to fall vertically downwardly and (c) the effect of centrifugal force urging the closure out of its circular path round the sorting track 6.

The purpose of causing the closures to rotate is to ensure that where an otherwise perfectly formed closure has one diameter undersize. it is guaranteed that that particular undersized diameter will at some stage span the two side plates 71! and 7h allowing the closure to be ejected.

In order to obstruct rotation of the closures to the minimum extent possible the fingers 2 are rectangular in cross-section in that their peripheral length l is greater than, in this case double. their axial width M.

In practice the width of the gap 12 between the two side plates 7a and 7h will be selected in order to eject undersize closures whose degree of undersize is outside the permitted tolerance. However, it may be desirable for the spacing between and 7b to be adjustable in order to vary the threshold at which undersize closures are ejected.

In use of the closure sorter illustrated in FIGS. I and 2. it has been found that closures which at first glance appear to be circular and correctly formed will be rejected even though they may only have a local diametral undersize of the order of I to 2 percent. This type of closure would almost certainly have passed unno' ticed through a conventional closure sorting device where no forced rotation of the closure is imparted.

The side plates 7a and 711 may be replaced by wires in which the appropriate serrations 9 and I0 are formed. Equally it is possible for such wires or for the side plates 71! and 7b to be augmented by upwardly extended side walls abutting but positioned outwardly of the two side plates 71! and 7b.

We claim:

I. A method of sorting skirted closures which comprises passing skirted closures along a sorting track having a rejecting slot dimensioned so as to receive undcrsized closures but to block correctly sized closures. rotating each closure about its axis of symmetry as it passes along the sorting track. collecting the closures which successfully pass along the sorting track and discarding any closures which pass through the rejecting slot.

2.. A method according to claim I in which each closure is rotated first in a first direction and subsequently in the opposite direction.

3. A method according to claim I in which the closures are rotated by serrations formed on the sorting track which engage the skirt of a closure passing along the track.

4. Sorting apparatus for skirted closures. which comprises a sorting track for transporting skirted closures. laterally spaced supporting surfaces to said track. means defining a closure rejecting slot in the supporting surfaces and serrated surface means formed on the sorting track and adapted to conform with the skirt of a closure passing along the track for driving the cltr sures in at least one direction of rotation.

5. Sorting apparatus according to claim 4 wherein said serrated surface means comprise a first serrated surface on one of said spaced supporting surfaces and a second serrated surface on the other of said spaced supporting surfaces.

6. Sorting apparatus according to claim 4 in which the said laterally spaced supporting surfaces are two spaced side plates and said serrated surface means comprise a first serrated surface on one of said side plates along a first part of the sorting track. and a second serrated surface on the second side plate along a second part of the sorting track.

7. Sorting apparatus according to claim 4 in which the said laterally spaced supporting surfaces are two spaced supporting wires. and said serrated surface means comprise a first serrated surface on one of said supporting wires along a first part of the sorting track and a second serrated surface on the second supporting wire along a second part of the sorting track.

8. Sorting apparatus according to claim 4 and including fingers for positively advancing closures along the sorting track. a rotary feed wheel carrying said fingers. and means mounting said fingers on said feed wheel for firm engagement with the sorting trackv 9. Sorting apparatus according to claim 8 wherein said finger mounting means comprise resilient biasing means permitting said fingers resiliently resisted motion in a radially inward direction.

10. Sorting apparatus according to claim 8 in which said sorting track is of arcuate form centered on the axis of rotation of the feed wheel, the said axis being horizontal and the sorting track subtending substantially at the axis of the feed wheel.

I l. Sorting apparatus according to claim 8. in which said fingers are rectangular in cross-section and have a length along the peripheral direction of the feed wheel and a width along the axial direction of the feed wheel.

said length being greater than said width.

* IF i 

1. A method of sorting skirted closures which comprises passing skirted closures along a sorting track having a rejecting slot dimensioned so as to receive undersized closures but to block correctly sized closures, rotating each closure about its axis of symmetry as it passes along the sorting track, collecting the closures which successfully pass along the sorting track and discarding any closures which pass through the rejecting slot.
 2. A method according to claim 1 in which each closure is rotated first in a first direction and subsequently in the opposite direction.
 3. A method according to claim 1 in which the closures are rotated by serrations formed on the sorting track which engage the skirt of a closure passing along the track.
 4. Sorting apparatus for skirted closures, which comprises a sorting track for transporting skirted closures, laterally spaced supporting surfaces to said track, means defining a closure rejecting slot in the supporting surfaces and serrated surface means formed on the sorting track and adapted to conform with the skirt of a closure passing along the track for driving the closures in at least one direction of rotation.
 5. Sorting apparatus according to claim 4 wherein said serrated surface means comprise a first serrated surface on one of said spaced supporting surfaces and a second serrated surface on the other of said spaced supporting surfaces.
 6. Sorting apparatus according to claim 4 in which the said laterally spaced supporting surfaces are two spaced side plates and said serrated surface means comprise a first serrated surface on one of said side plates along a first part of the sorting track, and a second serrated surface on the second side plate along a second part of the sorting track.
 7. Sorting apparatus according to claim 4 in which the said laterally spaced supporting surfaces are two spaced supporting wires, and said serrated surface means comprise a first serrated surface on one of said supporting wires along a first part of the sorting track and a second serrated surface on the second supporting wire along a second part of the sorting track.
 8. Sorting apparatus according to claim 4 and including fingers for positively advancing closures along the sorting track, a rotary feed wheel carrying said fingers, and means mounting said fingers on said feed wheel for firm engagement with the sorting track.
 9. Sorting apparatus according to clAim 8 wherein said finger mounting means comprise resilient biasing means permitting said fingers resiliently resisted motion in a radially inward direction.
 10. Sorting apparatus according to claim 8 in which said sorting track is of arcuate form centered on the axis of rotation of the feed wheel, the said axis being horizontal and the sorting track subtending substantially 90* at the axis of the feed wheel.
 11. Sorting apparatus according to claim 8, in which said fingers are rectangular in cross-section and have a length along the peripheral direction of the feed wheel and a width along the axial direction of the feed wheel, said length being greater than said width. 